#ifndef _LINUX_ELEVATOR_H
#define _LINUX_ELEVATOR_H
+#include <linux/percpu.h>
+
+#ifdef CONFIG_BLOCK
+
typedef int (elevator_merge_fn) (request_queue_t *, struct request **,
struct bio *);
typedef void (elevator_merge_req_fn) (request_queue_t *, struct request *, struct request *);
-typedef void (elevator_merged_fn) (request_queue_t *, struct request *);
+typedef void (elevator_merged_fn) (request_queue_t *, struct request *, int);
-typedef struct request *(elevator_next_req_fn) (request_queue_t *);
+typedef int (elevator_allow_merge_fn) (request_queue_t *, struct request *, struct bio *);
-typedef void (elevator_add_req_fn) (request_queue_t *, struct request *, int);
+typedef int (elevator_dispatch_fn) (request_queue_t *, int);
+
+typedef void (elevator_add_req_fn) (request_queue_t *, struct request *);
typedef int (elevator_queue_empty_fn) (request_queue_t *);
-typedef void (elevator_remove_req_fn) (request_queue_t *, struct request *);
-typedef void (elevator_requeue_req_fn) (request_queue_t *, struct request *);
typedef struct request *(elevator_request_list_fn) (request_queue_t *, struct request *);
typedef void (elevator_completed_req_fn) (request_queue_t *, struct request *);
typedef int (elevator_may_queue_fn) (request_queue_t *, int);
-typedef int (elevator_set_req_fn) (request_queue_t *, struct request *, int);
-typedef void (elevator_put_req_fn) (request_queue_t *, struct request *);
+typedef int (elevator_set_req_fn) (request_queue_t *, struct request *, gfp_t);
+typedef void (elevator_put_req_fn) (struct request *);
+typedef void (elevator_activate_req_fn) (request_queue_t *, struct request *);
+typedef void (elevator_deactivate_req_fn) (request_queue_t *, struct request *);
-typedef int (elevator_init_fn) (request_queue_t *, elevator_t *);
-typedef void (elevator_exit_fn) (request_queue_t *, elevator_t *);
+typedef void *(elevator_init_fn) (request_queue_t *);
+typedef void (elevator_exit_fn) (elevator_t *);
-struct elevator_s
+struct elevator_ops
{
elevator_merge_fn *elevator_merge_fn;
elevator_merged_fn *elevator_merged_fn;
elevator_merge_req_fn *elevator_merge_req_fn;
+ elevator_allow_merge_fn *elevator_allow_merge_fn;
- elevator_next_req_fn *elevator_next_req_fn;
+ elevator_dispatch_fn *elevator_dispatch_fn;
elevator_add_req_fn *elevator_add_req_fn;
- elevator_remove_req_fn *elevator_remove_req_fn;
- elevator_requeue_req_fn *elevator_requeue_req_fn;
+ elevator_activate_req_fn *elevator_activate_req_fn;
+ elevator_deactivate_req_fn *elevator_deactivate_req_fn;
elevator_queue_empty_fn *elevator_queue_empty_fn;
elevator_completed_req_fn *elevator_completed_req_fn;
elevator_init_fn *elevator_init_fn;
elevator_exit_fn *elevator_exit_fn;
+ void (*trim)(struct io_context *);
+};
- void *elevator_data;
+#define ELV_NAME_MAX (16)
+
+struct elv_fs_entry {
+ struct attribute attr;
+ ssize_t (*show)(elevator_t *, char *);
+ ssize_t (*store)(elevator_t *, const char *, size_t);
+};
+/*
+ * identifies an elevator type, such as AS or deadline
+ */
+struct elevator_type
+{
+ struct list_head list;
+ struct elevator_ops ops;
+ struct elv_fs_entry *elevator_attrs;
+ char elevator_name[ELV_NAME_MAX];
+ struct module *elevator_owner;
+};
+
+/*
+ * each queue has an elevator_queue associated with it
+ */
+struct elevator_queue
+{
+ struct elevator_ops *ops;
+ void *elevator_data;
struct kobject kobj;
- struct kobj_type *elevator_ktype;
- const char *elevator_name;
+ struct elevator_type *elevator_type;
+ struct mutex sysfs_lock;
+ struct hlist_head *hash;
};
/*
* block elevator interface
*/
+extern void elv_dispatch_sort(request_queue_t *, struct request *);
+extern void elv_dispatch_add_tail(request_queue_t *, struct request *);
extern void elv_add_request(request_queue_t *, struct request *, int, int);
extern void __elv_add_request(request_queue_t *, struct request *, int, int);
+extern void elv_insert(request_queue_t *, struct request *, int);
extern int elv_merge(request_queue_t *, struct request **, struct bio *);
extern void elv_merge_requests(request_queue_t *, struct request *,
struct request *);
-extern void elv_merged_request(request_queue_t *, struct request *);
-extern void elv_remove_request(request_queue_t *, struct request *);
+extern void elv_merged_request(request_queue_t *, struct request *, int);
+extern void elv_dequeue_request(request_queue_t *, struct request *);
extern void elv_requeue_request(request_queue_t *, struct request *);
extern int elv_queue_empty(request_queue_t *);
extern struct request *elv_next_request(struct request_queue *q);
extern void elv_unregister_queue(request_queue_t *q);
extern int elv_may_queue(request_queue_t *, int);
extern void elv_completed_request(request_queue_t *, struct request *);
-extern int elv_set_request(request_queue_t *, struct request *, int);
+extern int elv_set_request(request_queue_t *, struct request *, gfp_t);
extern void elv_put_request(request_queue_t *, struct request *);
/*
- * noop I/O scheduler. always merges, always inserts new request at tail
+ * io scheduler registration
*/
-extern elevator_t elevator_noop;
+extern int elv_register(struct elevator_type *);
+extern void elv_unregister(struct elevator_type *);
/*
- * deadline i/o scheduler. uses request time outs to prevent indefinite
- * starvation
+ * io scheduler sysfs switching
*/
-extern elevator_t iosched_deadline;
+extern ssize_t elv_iosched_show(request_queue_t *, char *);
+extern ssize_t elv_iosched_store(request_queue_t *, const char *, size_t);
+
+extern int elevator_init(request_queue_t *, char *);
+extern void elevator_exit(elevator_t *);
+extern int elv_rq_merge_ok(struct request *, struct bio *);
/*
- * anticipatory I/O scheduler
+ * Helper functions.
*/
-extern elevator_t iosched_as;
+extern struct request *elv_rb_former_request(request_queue_t *, struct request *);
+extern struct request *elv_rb_latter_request(request_queue_t *, struct request *);
/*
- * completely fair queueing I/O scheduler
+ * rb support functions.
*/
-extern elevator_t iosched_cfq;
-
-extern int elevator_init(request_queue_t *, elevator_t *);
-extern void elevator_exit(request_queue_t *);
-extern int elv_rq_merge_ok(struct request *, struct bio *);
-extern int elv_try_merge(struct request *, struct bio *);
-extern int elv_try_last_merge(request_queue_t *, struct bio *);
+extern struct request *elv_rb_add(struct rb_root *, struct request *);
+extern void elv_rb_del(struct rb_root *, struct request *);
+extern struct request *elv_rb_find(struct rb_root *, sector_t);
/*
* Return values from elevator merger
#define ELEVATOR_INSERT_FRONT 1
#define ELEVATOR_INSERT_BACK 2
#define ELEVATOR_INSERT_SORT 3
+#define ELEVATOR_INSERT_REQUEUE 4
+/*
+ * return values from elevator_may_queue_fn
+ */
+enum {
+ ELV_MQUEUE_MAY,
+ ELV_MQUEUE_NO,
+ ELV_MQUEUE_MUST,
+};
+
+#define rq_end_sector(rq) ((rq)->sector + (rq)->nr_sectors)
+#define rb_entry_rq(node) rb_entry((node), struct request, rb_node)
+
+/*
+ * Hack to reuse the donelist list_head as the fifo time holder while
+ * the request is in the io scheduler. Saves an unsigned long in rq.
+ */
+#define rq_fifo_time(rq) ((unsigned long) (rq)->donelist.next)
+#define rq_set_fifo_time(rq,exp) ((rq)->donelist.next = (void *) (exp))
+#define rq_entry_fifo(ptr) list_entry((ptr), struct request, queuelist)
+#define rq_fifo_clear(rq) do { \
+ list_del_init(&(rq)->queuelist); \
+ INIT_LIST_HEAD(&(rq)->donelist); \
+ } while (0)
+
+/*
+ * io context count accounting
+ */
+#define elv_ioc_count_mod(name, __val) \
+ do { \
+ preempt_disable(); \
+ __get_cpu_var(name) += (__val); \
+ preempt_enable(); \
+ } while (0)
+
+#define elv_ioc_count_inc(name) elv_ioc_count_mod(name, 1)
+#define elv_ioc_count_dec(name) elv_ioc_count_mod(name, -1)
+
+#define elv_ioc_count_read(name) \
+({ \
+ unsigned long __val = 0; \
+ int __cpu; \
+ smp_wmb(); \
+ for_each_possible_cpu(__cpu) \
+ __val += per_cpu(name, __cpu); \
+ __val; \
+})
+
+#endif /* CONFIG_BLOCK */
#endif
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